[Effects of pre-electroacupuncture on blood pressure and cardiac function in high-salt-induced hypertension rats].

OBJECTIVE: To observe the effects of pre-electroacupuncture at "Taichong"(LR3), "Neiguan"(PC6) and "Waiguan"(TE5) on blood pressure and cardiac function of high-salt-induced hypertension rats, so as to explore the possible mechanism of pre-electroacupuncture in improving hypertension. METHODS: Twenty-four SD rats were randomly divided into control group, high-salt group and pre-electroacupuncture group, with 8 rats in each group. The hypertension model was established by feeding high-salt diet for 7 weeks. In the pre-electroacupuncture group, rats received electroacupuncture intervention at bilate-ral LR3, PC6 and TE5 (2 Hz/15 Hz, 2 mA) for 30 min, once a day, from the first day of modeling, for a total of 7 weeks. The blood pressure of rats was monitored by caudal artery noninvasive blood pressure measurement technique before and at the 1st, 3rd, 5th and 7th week of modeling. At the 8th week of the experiment, left ventricular catheterization was performed and biological signal acquisition system was used to detect left ventricular hemodynamics indexes and analyze left ventricular function, the car-diac mass ratio was measured to evaluate the degree of myocardial hypertrophy. The mRNA expressions of atrial natriuretic peptide(ANP), myosin heavy chain 7(MYH7), α-smooth muscle actin(α-SMA), interleukin(IL)-1ß, and IL-6 of myocardial tissues were detected by quantitative real-time PCR. Sirius red staining was used to observe the degree of myocardial fibrosis. RESULTS: Compared with the control group, systolic blood pressure, diastolic blood pressure, mean arterial pressure, left ventricular end-diastolic pressure (LVEDP), cardiac mass ratio，and the mRNA expressions of ANP, MYH7, α-SMA, IL-1ß, and IL-6, and sirius red staining area of myocardium were all significantly increased(P<0.01,P<0.05)，maximal rate of rise and descent of left ventricular pressure(LVP±dP/dtmax) were decreased (P<0.05,P<0.01) in the high-salt group. Compared with the high-salt group, rats in the pre-electroacupuncture group had lower systolic blood pressure, diastolic blood pressure, mean arterial pressure, LVEDP，cardiac mass ratio，higher LVP±dP/dtmax,down-regulated mRNA expressions of ANP, MYH7, α-SMA, IL-1ß, IL-6, and smaller area of sirius red staining(P<0.05, P<0.01). CONCLUSION: Pre-electroacupuncture tends to lower blood pressure, improve cardiac function and reduce myocardial fibrosis in high-salt-induced hypertension rats, which may be associated with inhibiting inflammatory response.

The Effect of Pre-Electroacupuncture on Nociceptive Discharges of Spinal Wide Dynamic Range Neurons in Rat.

Purpose: Spinal wide dynamic range (WDR) neurons are well studied in pain models and they play critical roles in regulating nociception. Evidence has started to accumulate that acupuncture produces a good analgesic effect via activating different primary fibers with distinct intensities. The purpose of the present study was to compare the distinct intensities of pre-electroacupuncture (pre-EA) at local muscular receptive fields (RFs), adjacent or contralateral non-RFs regulating the nociceptive discharges of spinal WDR neurons evoked by hypertonic saline (HS). Materials and Methods: Spinal segments of electrophysiological recording were identified by neural tracers applied at the left gastrocnemius muscle. The thresholds of Aß (TAß), Aδ (TAδ) and C (TC) components of WDR neurons were measured to determine the intensity of pre-EA by extracellular recording. The discharges of WDR neurons induced by distinct intensities of pre-EA and 200 µL HS (6%) injection in left gastrocnemius muscle of rats were observed by extracellular recording. Results: The spinal segments of WDR neurons were confirmed in lumbar (L)5-6 area according to the projective segments of dorsal root ganglion. TAß, TAδ and TC of WDR neurons was determined to be 0.5, 1, and 2 mA, respectively. The pre-EA with intensities of TAß (P < 0.05), TAδ (P < 0.05), TC (P < 0.05) or 2TC (P < 0.01) at ipsilateral adjacent non-RFs significantly reduced the discharges of WDR neurons, while at local RFs only pre-EA of TAδ (P < 0.05), TC (P < 0.05) and 2TC (P < 0.01) could inhibit the nociceptive discharges. In addition, intensity of pre-EA at contralateral non-RFs should reach at least TC to effectively inhibit the firing rates of WDR neurons (P < 0.01). Conclusion: Pre-EA could suppress nociceptive discharges of WDR neurons and the inhibitory effects were dependent on the distinct intensities and locations of stimulation.

[Comparison of effects of routine electroacupuncture and pre-electroacupuncture in improving lung function in acute lung injury rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) and pre-EA at"Taiyuan"(LU9) on histopathological changes, pulmonary ventilation function, pneodynamics, and contents of TNF-α, IL-1ß and IL-10 in the bronchoalveolar lavage fluid in rats with acute lung injury (ALI), in order to explore their differences of therapeutic effects. METHODS: A total of 92 male SD rats were randomly divided into control, model, routine EA and pre-EA groups, with 23 rats in each group. The ALI rat model was established by instillation of 0.5% lipopolysaccharide solution (5 mg/kg) intratracheally. EA (3 mA, 10 Hz) was applied to bilateral LU9 for 20 min, once 5 h after modeling for rats of the routine EA group, and once on the 1st, 3rd and 5th day respectively before modeling for rats of the pre-EA group. The pulmonary ventilation functions, including dynamic lung compliance (Cdyn), tidal volume (TV)，minute ventilation volume (MV), lung resistance, peak inspiratory flow (PIF), peak expiratory flow (PEF), were measured by using a small animal lung function detection system. The electromyogram (EMG) of the diaphragm muscle was recorded for observing changes of the total integral electromyogram(iEMG), single iEMG and respiration rate. Pathological changes of the lung tissue were scored after H.E. staining. The contents of TNF-α, IL-1ß and IL-10 in the bronchoalveolar lavage fluid were determined by enzyme linked immunosorbent assay. RESULTS: Compared with the control group, the Cdyn, TV, MV and PIF consi-derably decreased (P<0.000 1), and the lung resistance, total iEMG of diaphragm muscle, lung injury score, and contents of TNF-α and IL-1ß were significantly increased (P<0.05, P<0.001, P<0.01) in the model group. In comparison with the model group, the TV, MV and PIF in both routine EA and pre-EA groups,and the Cdyn, total iEMG and single iEMG in the routine EA group, as well as the IL-10 content in the pre-EA group were significantly increased (P<0.01, P<0.001, P<0.05), whereas the lung injury score, and contents of TNF-α and IL-1ß were significantly decreased in the pre-EA group (P<0.05). CONCLUSION: Both pre-EA and routine EA at LU9 can improve the lung function of ALI model rats. Pre-electroacupuncture is related to local immunoregulation, while electroacupuncture is mainly related to the improvement of pulmonary ventilation function and respiratory motility.

[Effect of electroacupuncture and pretreatment of electroacupuncture on pain sensitization and expression of P2X7R in spinal dorsal horn in rats with diabetic neuropathic pain].

OBJECTIVE: To observe the occurrence time of neuralgia and the expression of purinergic ligand-gated ion channel 7 receptor (P2X7R) in the dorsal horn of the spinal cord after intraperitoneal injection of streptozotocin (STZ) in diabetic rats, and to explore the effect of electroacupuncture (EA) and pretreatment of EA on the heat pain threshold and expression of P2X7R in the spinal dorsal horn in rats with diabetic neuropathic pain (DNP), and to explore the possible mechanism of EA for DNP. METHODS: PartⅠ: Thirty male SD rats were randomly selected from 64 male SD rats as the control group; the remaining rats were given intraperitoneal injection of STZ (10 mg/mL) at a dose of 65 mg/kg to establish the diabetes model, and 30 rats were successfully modeled as the model group. The control group and the model group were divided into three subgroups respectively at 7, 14 and 21 days, with 10 rats in each subgroup. Body mass, fasting blood glucose (FBG) and thermal pain threshold were recorded at 7, 14 and 21 days after injection; the expression of P2X7R in spinal dorsal horn was detected by Western blot. PartⅡ: Eight SD rats were randomly selected from 35 male SD rats as the blank group, and the remaining 27 rats were given intraperitoneal injection of STZ (10 mg/mL) at a dose of 65 mg/kg to establish the diabetes model. The 24 rats with successful diabetes model were randomly divided into a DNP group, an EA group and a pre-EA group, 8 rats in each group. Fifteen to 21 days after STZ injection, the EA group received EA at "Zusanli" (ST 36) and "Kunlun" (BL 60), continuous wave, frequency of 2 Hz, 30 min each time, once a day; the intervention method in the pre-EA group was the same as that in the EA group. The intervention time was 8 to 14 days after STZ injection. The body mass, FBG and thermal pain threshold were recorded before STZ injection and 7, 14 and 21 days after STZ injection; the expression of P2X7R in spinal dorsal horn was detected by Western blot 21 days after injection. RESULTS: PartⅠ: Compared with the control group, in the model group, the body mass was decreased and FBG was increased 7, 14 and 21 days after STZ injection (P<0.01), and the thermal pain threshold was decreased 14 and 21 days after STZ injection (P<0.05), and the expression of P2X7R in spinal dorsal horn was increased 7, 14 and 21 days after STZ injection (P<0.05, P<0.01). PartⅡ: Compared with the blank group, in the DNP group, the body mass was decreased and fasting blood glucose were increased 7, 14 and 21 days after STZ injection (P<0.01). Compared with the DNP group, in the pre-EA group, the heat pain threshold was increased 14 and 21 days after STZ injection (P<0.05), while in the EA group, the heat pain threshold was increased 21 days after STZ injection (P<0.01), and the expression of P2X7R in the dorsal horn in the EA group and the pre-EA group was decreased (P<0.01). CONCLUSION: The diabetic neuropathic pain is observed 14 days after STZ injection. EA could not only treat but also prevent the occurrence of DNP, and its mechanism may be related to down-regulation of P2X7R expression in the dorsal horn of the spinal cord.

Effect of electroacupuncture and pretreatment of electroacupuncture on pain sensitization and expression of P2X7R in spinal dorsal horn in rats with diabetic neuropathic pain / 中国针灸

OBJECTIVE@#To observe the occurrence time of neuralgia and the expression of purinergic ligand-gated ion channel 7 receptor (P2X7R) in the dorsal horn of the spinal cord after intraperitoneal injection of streptozotocin (STZ) in diabetic rats, and to explore the effect of electroacupuncture (EA) and pretreatment of EA on the heat pain threshold and expression of P2X7R in the spinal dorsal horn in rats with diabetic neuropathic pain (DNP), and to explore the possible mechanism of EA for DNP.@*METHODS@#PartⅠ: Thirty male SD rats were randomly selected from 64 male SD rats as the control group; the remaining rats were given intraperitoneal injection of STZ (10 mg/mL) at a dose of 65 mg/kg to establish the diabetes model, and 30 rats were successfully modeled as the model group. The control group and the model group were divided into three subgroups respectively at 7, 14 and 21 days, with 10 rats in each subgroup. Body mass, fasting blood glucose (FBG) and thermal pain threshold were recorded at 7, 14 and 21 days after injection; the expression of P2X7R in spinal dorsal horn was detected by Western blot. PartⅡ: Eight SD rats were randomly selected from 35 male SD rats as the blank group, and the remaining 27 rats were given intraperitoneal injection of STZ (10 mg/mL) at a dose of 65 mg/kg to establish the diabetes model. The 24 rats with successful diabetes model were randomly divided into a DNP group, an EA group and a pre-EA group, 8 rats in each group. Fifteen to 21 days after STZ injection, the EA group received EA at "Zusanli" (ST 36) and "Kunlun" (BL 60), continuous wave, frequency of 2 Hz, 30 min each time, once a day; the intervention method in the pre-EA group was the same as that in the EA group. The intervention time was 8 to 14 days after STZ injection. The body mass, FBG and thermal pain threshold were recorded before STZ injection and 7, 14 and 21 days after STZ injection; the expression of P2X7R in spinal dorsal horn was detected by Western blot 21 days after injection.@*RESULTS@#PartⅠ: Compared with the control group, in the model group, the body mass was decreased and FBG was increased 7, 14 and 21 days after STZ injection (P<0.01), and the thermal pain threshold was decreased 14 and 21 days after STZ injection (P<0.05), and the expression of P2X7R in spinal dorsal horn was increased 7, 14 and 21 days after STZ injection (P<0.05, P<0.01). PartⅡ: Compared with the blank group, in the DNP group, the body mass was decreased and fasting blood glucose were increased 7, 14 and 21 days after STZ injection (P<0.01). Compared with the DNP group, in the pre-EA group, the heat pain threshold was increased 14 and 21 days after STZ injection (P<0.05), while in the EA group, the heat pain threshold was increased 21 days after STZ injection (P<0.01), and the expression of P2X7R in the dorsal horn in the EA group and the pre-EA group was decreased (P<0.01).@*CONCLUSION@#The diabetic neuropathic pain is observed 14 days after STZ injection. EA could not only treat but also prevent the occurrence of DNP, and its mechanism may be related to down-regulation of P2X7R expression in the dorsal horn of the spinal cord.